Update dotnet-docker image for v7.7.0-preview.2

[daxian-dbw]

Update dotnet-docker image for v7.7.0-preview.2 release.

[daxian-dbw]

There is one failure due to authentication when calling Invoke-WebRequest -Uri 'https://graph.microsoft.com'.
@lbussell Can you please take a look and check if it's a known issue?

##[debug]Agent environment resources - Disk: C:\ Available 97295.09 MB out of 129548.00 MB, Memory: Used 4262.00 MB out of 8191.00 MB, CPU: Usage 100.00%
##[debug]Agent environment resources - Disk: C:\ Available 97246.29 MB out of 129548.00 MB, Memory: Used 4421.00 MB out of 8191.00 MB, CPU: Usage 78.00%
[xUnit.net 00:00:09.68]     Microsoft.DotNet.Docker.Tests.PowerShellTests.VerifyPowerShellScenario_InvokeWebRequest(imageData: ProductImageData { Arch = Amd64, IsArm = False, OS = nanoserver-ltsc2025, IsDistroless = False, DefaultPort = 8080, NonRootUID = , Platform = windows/amd64, ArchVariant = , IsWindows = True, Rid = win-x64, OsVersion = ltsc2025, HasCustomSdk = False, GlobalizationInvariantMode = False, SupportsPowerShell = True, SupportsDnx = True, SdkOS = nanoserver-ltsc2025, SdkImageVariant = None, OSTag = nanoserver-ltsc2025, OSDir = nanoserver-ltsc2025, Version = 10.0, VersionFamily = 10.0, ImageVariant = None, SupportedImageRepos = SDK, Runtime, Runtime_Deps, Aspnet, VersionString = 10.0 }) [FAIL]
  Failed Microsoft.DotNet.Docker.Tests.PowerShellTests.VerifyPowerShellScenario_InvokeWebRequest(imageData: ProductImageData { Arch = Amd64, IsArm = False, OS = nanoserver-ltsc2025, IsDistroless = False, DefaultPort = 8080, NonRootUID = , Platform = windows/amd64, ArchVariant = , IsWindows = True, Rid = win-x64, OsVersion = ltsc2025, HasCustomSdk = False, GlobalizationInvariantMode = False, SupportsPowerShell = True, SupportsDnx = True, SdkOS = nanoserver-ltsc2025, SdkImageVariant = None, OSTag = nanoserver-ltsc2025, OSDir = nanoserver-ltsc2025, Version = 10.0, VersionFamily = 10.0, ImageVariant = None, SupportedImageRepos = SDK, Runtime, Runtime_Deps, Aspnet, VersionString = 10.0 }) [6 s]
  Error Message:
   System.InvalidOperationException : Failed to execute docker run --name 10.0-pwsh-134243866841346594 --rm  mcr.microsoft.com/dotnet/nightly/sdk:10.0-nanoserver-ltsc2025 pwsh -nologo -noprofile -c (Invoke-WebRequest -Uri 'https://graph.microsoft.com').statuscode/
Exit code: 1
Standard Error: Invoke-WebRequest: Authentication failed, see inner exception.
  Stack Trace:
     at Microsoft.DotNet.Docker.Tests.DockerHelper.Execute(String args, Boolean ignoreErrors, Boolean autoRetry, ITestOutputHelper outputHelper) in C:\a\_work\1\s\dotnet-docker\tests\Microsoft.DotNet.Docker.Tests\DockerHelper.cs:line 219
   at Microsoft.DotNet.Docker.Tests.DockerHelper.ExecuteWithLogging(String args, Boolean ignoreErrors, Boolean autoRetry) in C:\a\_work\1\s\dotnet-docker\tests\Microsoft.DotNet.Docker.Tests\DockerHelper.cs:line 234
   at Microsoft.DotNet.Docker.Tests.DockerHelper.Run(String image, String name, String command, String workdir, String optionalRunArgs, Boolean detach, String runAsUser, Boolean skipAutoCleanup, Boolean useMountedDockerSocket, Boolean silenceOutput, Boolean tty) in C:\a\_work\1\s\dotnet-docker\tests\Microsoft.DotNet.Docker.Tests\DockerHelper.cs:line 369
   at Microsoft.DotNet.Docker.Tests.PowerShellTests.PowerShellScenario_Execute(ProductImageData imageData, String command, String optionalArgs) in C:\a\_work\1\s\dotnet-docker\tests\Microsoft.DotNet.Docker.Tests\PowerShellTests.cs:line 127
   at Microsoft.DotNet.Docker.Tests.PowerShellTests.VerifyPowerShellScenario_InvokeWebRequest(ProductImageData imageData) in C:\a\_work\1\s\dotnet-docker\tests\Microsoft.DotNet.Docker.Tests\PowerShellTests.cs:line 104
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
  Standard Output Messages:
 Executing: docker run --name 10.0-pwsh-134243866841346594 --rm  mcr.microsoft.com/dotnet/nightly/sdk:10.0-nanoserver-ltsc2025 pwsh -nologo -noprofile -c (Invoke-WebRequest -Uri 'https://graph.microsoft.com').statuscode/
 \x1b[31;1mInvoke-WebRequest: \x1b[31;1mAuthentication failed, see inner exception.\x1b[0m